The following description is provided to assist the understanding of the reader. None of the information provided or references cited is admitted to be prior art to the present invention.
Malaria is one of the major protozoan diseases and afflicts more than 500 million people (mostly in developing countries). Each year, malaria infections kill between one and two million people, most of whom are children. In humans, malaria is caused by four different protozoa species of the genus Plasmodium, with P. falciparum being the most lethal. The life cycle of the parasite is very complex and proceeds through several asexual and sexual stages (Malaria: Parasite Biology, Pathogenesis, and Protection; Sherman, I. W., Ed. ASM Press: Washington, D.C., 1998). Plasmodium sporozoites are transmitted by female Anopheles mosquitoes and are injected in the blood of a human host. The initial proliferation takes place in the liver and merozoites are formed which are released back into the blood stream. The parasite then invades red blood cells (RBCs) and matures, forming a ring-shaped cell. Within 24 h, the matured parasite enters the trophozoite stage where it catabolizes most of the RBC cytoplasm. Through the final (schizont) stage, the parasite undergoes several divisions to produce up to 32 new merozoites that burst the host RBC and invade new erythrocytes.
Chemical and biological sensors are devices that can detect or quantify analytes by virtue of interactions between targeted analytes and macromolecular binding agents such as, but not limited to, enzymes, receptors, heavy metal chelators, or antibodies. Chemical and biological sensors are commonly categorized according to two features, namely, the type of material utilized as binding agent and the means for detecting an interaction between binding agent and targeted analyte or analytes. Major classes of biosensors include enzyme (or catalytic) biosensors, immunosensors and DNA biosensors. Chemical sensors make use of synthetic macromolecules for detection of target analytes. Some common methods of detection are based on electron transfer, generation of chromophores, or fluorophores, changes in optical or acoustical properties, or alterations in electric properties when an electrical signal is applied to the sensing system. For example, upon interaction with an analyte, an enzyme may generate electrons, a colored chromophore or a change in pH (due to release of protons) as the result of the relevant catalytic enzymatic reaction. Alternatively, upon interaction with an analyte, an enzyme may cause a change in a fluorescent or chemiluminescent signal that can be recorded by an appropriate detection system.